In a system for buying and selling items such as an auction system, a user as a buyer may mark a user as a seller as favorite. For example, a bidder in an auction system marks as favorite a seller of items successfully bidded and a seller who sells items of favorite.
In addition to the self favorite by the user, there is a technology that the system may recommend other user who is favorited by the user.
Patent Document 1 below describes that one user is recommended to another user if both users give highest points and lowest points to the same items or service to be evaluated.
Patent Document 1: Japanese Patent Application Laid-open No. 2009-123192